Conventionally, image processing techniques have been developed, which find a motion vector of a subject from among a plurality of images.
For example, a technique to roughly detect a motion vector in an image the resolution of which has been reduced, and then to detect with high precision a motion vector in an image of high resolution (Patent Document 1) and a technique to detect a motion vector of an image by comparing projection components of an image (Patent Document 2) have been disclosed.    Patent Document 1: U.S. Pat. No. 5,477,272    Patent Document 2: U.S. Pat. No. 6,463,164